Thanks. The problem is I have an variable number of these indices. I
have figured part of it out and it involves a code like this with the
indented column being the important one. Of course I work on this for 4
hours and figure part of it out about 2 minutes after posting. The
answer involves subsetting directly on a matched level value.
spec.fact<-substring(names(spec.count),1,4)
spec.col <- data.frame(ni(spec.count),spec.fact)
spec.fact2 <- factor(spec.fact)
spec.fact2
i<-7
spec.sub<- spec.col[spec.col[,3]==levels(spec.fact2)[i],]
spec.wk <- frcheck[,spec.sub[,2]]
dim(spec.wk)
Ken
________________________________
From: nalluri pratap [mailto:[EMAIL PROTECTED]
Sent: Wednesday, September 20, 2006 4:03 PM
To: Pierce, Ken
Subject: Re: [R] problem coercing truncated character vector to levels
hi,
Try this one
spec.count<- strtrim(c("abco_1", "abco_2", "abco_3", "psm_1", "psme_2",
"psme_3"),c(4,4,4,3,4,4))
spec.groups <- unique(spec.count)
pmatch(spec.groups[1],spec.fact)
Thanks and Regards,
Pratap
"Pierce, Ken" <[EMAIL PROTECTED]> wrote:
Dear R wizes,
I have a data.frame of species abundances with column names
consisting
of 4 letter codes then an underscore and a number like this:
abco_1, abco_2, abco_3, psm_1, psme_2, psme_3, etc.
I would like to get an identifier for all the abco, and psme and
other
species etc.
I used
spec.fact<-substring(names(spec.count),1,4)
To make a vector of the first 4 letters of each name. I tried
using
spec.groups <- unique(spec.fact)
and then matching
pmatch(spec.groups[1],spec.fact)
to get out the indexes of all the columns that match the second
unique
value, i.e what are the column number for all the abco columns.
Then I
could make a temporary data.frame of just the abco columns. I
could loop
through the unique vector spec.groups to do this for each group
and
perform the operations I need to on each individual
mini-dataframe.
Unfortunately the matching doesn't work. Any suggestions?
Ken
Kenneth B. Pierce Jr.
Research Ecologist
Landscape Ecology, Modeling, Mapping and Analysis Team
PNW Research Station - USDA-FS
3200 SW Jefferson Way, Corvallis, OR 97331
[EMAIL PROTECTED]
541 750-7393
http://www.fsl.orst.edu/lemma/gnnfire
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